It is desirable for a scroller jig saw to be able to operate in both a scrolling and a non-scrolling mode. In the scrolling mode the operator needs to be able to control rotation of the saw blade about its longitudinal axis, while in the non-scrolling mode the saw blade needs to be locked against such rotation. It is important that the saw blade can be locked in the conventional position, namely with the cutting edge of the saw blade facing directly forwards, but it is also desirable that the saw blade should be lockable in other angular positions.
A variety of mechanisms for achieving the controls mentioned above have been proposed, and examples of such mechanisms are to be found in U.S. Pat. Nos. 3,494,390; 3,729,822; and 4,283,855. While various mechanisms have been proposed, there is still a need for a simple and reliable mechanism which facilitates switching between scrolling and non-scrolling modes.